A general formulation of the echo received from a random scatterer ensemble illuminated by a short electromagnetic or sonic signal is developed. It is shown theoretically and confirmed experimentally with ultrasound, that a gradient in scatterer density will return an echo which is partially spatially coherent (i.e. specular). The surface of a random ensemble of uniform scatterers is shown to produce an echo from whose degree of coherence, the scatterer density and cross section can be calculated.
SiegertA.J.GoldsteinH., Coherent and Incoherent Scattering from Assemblies of Scatterers, Appendix B, in Propagation of Short Radio Waves (ed. KerrD.E.), Vol. 13, M.I.T. Radiation Lab. Series, (McGraw-Hill, New York, 1948).
2.
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3.
GlotovV.P., Coherent scattering of sound from clusters of discrete inhomo-geneities in pulsed emission, Soviet Physics-Acoustics, 8, 220–222, (1963). Translated from Akusticheskii Zhurnal, 8, 281–284, (1962).
4.
MorseP.M.IngardK.U., Theoretical Acoustics, (McGraw-Hill, New York, 1968).
5.
NewhouseV.L.AmirI.YuG., On the Creation of a Coherent Echo from Random Media, in Proc. IEEE Ultrasonics Symposium, (1984), to be published.
6.
GoebbelsK., About the origin of the high-frequency ultrasonic backscattering signals, Material Prüfung24, 314–316, (1982).
7.
NewhouseV.L.AmirI., On the creation of a coherent echo from random media, Ultrasonic Imaging7105 (1985). (Abstract only).
